Descartes uses the term "conscientia" (conscience) to apply both to consciousness of thinking and to the act of thinking itself. These are two different sorts of consciousness, And they stand in different relations to their objects. Consciousness as a way of thinking (c1) is neither necessary nor sufficient for the existence of its object. Consciousness of thinking (c2) is both necessary and sufficient for the existence of its object. The distinction between c1 and c2 provides descartes with a way out of hobbes's infinite regress and frees descartes from problematic theses concerning the evidence and incorrigibility of mental states